Floating snake antenna



Dec. 11, 1962 J. J. TENNYSON FLOATING SNAKE ANTENNA 3 Sheets-Sheet 1Filed Sept. 18, 1959 INVENTOR. Jimi: J 72AM ys /v HTTOPA/tiV- Dec. 11,1962 J. J. TENNYSON FLOATING SNAKE ANTENNA Filed Sept. 18, 1959 5Sheets-She 2 INVENTOR. li/n55 J ZEN 7 Decv 11, 1962 J. J. TENNYSONFLOATING SNAKE ANTENNA 3 Sheets-Shet; 3

Filed Sept. 18, 1959 INVENTOR JZ/ma I fi/wvyw/r /77 rae/vsw.

United States Patent 3,068,477 FLOATING SNAKE ANTENNA James J. Tennyson,32 Brill Ave., Waterford, Conn. l iled Sept. 18, 1959, Ser. No. 840,98012 Claims. c1. 34s 70e) (Granted under Title 35, US. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

This invention relates to electrical antennas that are used withreceivers or transmitters located aboard small vessels, lifeboat orrafts, and more particularly with 1nflatable and deflatable floatingwire antennas.

It is common practice to equip buoys, lifeboats and rafts with radioreceiving and transmitting equipment for communication and transmissionof position information. The present practice is to employ a vertical whp antenna in conjunction with the radio system. The whip antenna iseither mounted directly to the lifeboator raft or supported by a balloontied to the raft. Sufficient antenna height in all kinds of weather isnot assured where vertical whip antennas are employed due 1n part to seaconditions. Pitching and tossing of the craft changes the impedance ofthe antenna and consequently the eificiency of transmission is severelyreduced and water spray tends to short the antenna and acceleratecorrosion. Constant maintenance of the antenna is required when in usein order to insure some transmission of intelligence. The problemsoutlined above become acute as the frequency of transmission isincreased and so the radio system may be limited to relatively lowfrequencies.

An object of this invention is to provide a floating antenna systemwhich may be collapsed endwise when not in use, but easily and quicklyexpanded when use is desired, and which will operate satisfactorily overa large frequency spectrum when exposed to changing ocean atmosphericconditions.

Another object of this invention is to provide a floating antenna systemfor vessels which will have a constant antenna height under all floatingconditions and will not be shorted or corroded by sea spray irrespectiveof the sea state, and may be, when required, readily sunk by its user.

A further object of this invention is to provide a simple, inexpensive,practical, compact, eflicient and inexpensive antenna system forvessels.

Other objects and advantages will be apparent from the followingdescription of an embodiment of the invention, and the novel featuresthereof will be particularly pointed out hereinafter in connection withthe appended claims.

FIG. l is a perspective of a portion of an embodiment made in accordancewith this invention, with a portion of the casing removed,

FIG. 2 is a side elevation of the embodiment in a collapsed or deflatedcondition,

FIG. 3 is a side elevation of the embodiment when emploved inconjunction with a raft,

FIG. 4 is a section of a portion of the embodiment of FIG. 2 takenapproximately lengthwise through the center, and

FIG. 5 is similar to FIG. 3 except that the antenna has been inflated.

The same identification numbers are used in the various figures toidentify the same or corresponding parts in the various illustrations.

In the embodiment of the invention illustrated in FIG. 1, a hollow,elongated, elastic, closed, watertight casing 6 of electricallyinsulating flexible sheet material, as for exp nyl or any suitableflexible and water imperice vious plastic sheet material which containstherein electrically insulating disk spacers 7 arranged in seriatim atspaced apart intervals along the length of the casing with their facestransverse to the longitudinal axis 8 of the casing. The casing 6 ispreferably cylindrical and the disks of a diameter so as to fit snuglywithin, and abut the inner wall of the casing. The peripheral edge 9 ofeach disk is aflixed to the casing abutting that edge by any suitablemethod as for example by an appropriate waterproof cement or adhesivethereby confining the disk against lengthwise movement relative to thecasing. Each disk 7 has a plurality of passage 10 extending therethroughfrom face to face in order to allow free passage of gas with- -in thecasing when the casing is extended and a flexible electricallyconducting antenna wire 11 extending in a direction lengthwise of andwithin the casing is supported centrally of the casing by the disks 7.The wire 11 may be supported by the disks in any suitable mannerprovided the wire is thusly insulated from the casing 6, as for example,by providing each disk with an aperture 12 at its center through whichthe wire passes and that portion of the wire within the aperture 12 maybe cemented to the inner peripheral edge of the disk aperture 12 toconfine the wire against lengthwise movement. The disk spaces the wirefrom the casing equally on all sides so that the wire will always be thesame distance from the water on which the antenna floats and rolls.

In order to permit compact storage and ease of handling, the casing 6may be provided with an accordian pleat construction and thereby may bereadily collapsed or deflated as is illustrated in FIG. 2. The end walls14 and 15 of the casing are disk-like rigid plastic members hermeticallysealed to the casing so as to form a water and air tight joint. A shortconduit 13 extends through an opening and beyond in one end wall 14 ofthe casing and in so doing is provided with a tight seal at itsperiphery so as to prevent the passage of water into casing 6 or theescape of gas from within the casing. A check valve (not shown) isdisposed within the conduit 13 whereby the casing may be inflated ordistended by the admission of gas under pressure through the check valvefrom a suitable source of compressed gas, as for example, container 18and deflated by means of the check valve. The gas so introduced, fillsthe entire casing passing through openings 10 in the disk spacers 7. Theantenna wire 11 which is centrally disposed within the casing extendsfrom one end wall 15 of the casing where it may be attached, along thelongitudinal axis of the casing through an aperture 16 in the oppositeend wall 14 and beyond. A tight seal is provided between the antennawire 11 and the inner peripheral wall of aperture 16 so as to preventthe escape of gas from and the admission of water into the casing. Thatportion of the wire 11 exterior to the casing has an insulated coating17 and may be also used as a tow line between the raft or lifeboat 20and the floating antenna 21 as illustrated in FIG. 3. A separate towline may be aflixed to the casing walls 14 or 15 where additionalstrength is required or where sea conditions will so warrant and anotherelectrical connection provided for the antenna wire 11 to the raft 20.

A sectional portion of one form of the floating antenna is illustratedin FIG. 4 wherein the casing construction allows the antenna casing 6 tofold as shown so that the disks 7 are closely spaced in a face to facerelationship, and the portion of the flexible antenna wire 11 which isdisposed between the individual disks 7 is bent into a U shape when thefloating antenna is collapsed. It is evident from the showing of FIGURE4 that the antenna wire itself when bent into a U shape upon collapse ofthe antenna can extend out to the peripheral edge of the disk 7. Sincethe wire is so shaped, its maximum length between disks would beapproximately equal to the diameter of the disk provided there existedonly one U bend of the antenna wire between adjacent disks. In otherwords, the wire first extends out from the center to the edge of thedisk and then back thereby being equal to two radii, or the diameter ofthe casing. The disk thickness is very small as compared to its diameterand therefore the approximate length of the antenna when fully inflated(extended) is equal to the number of disks multiplied by their diameter.Of course, where multiple U bends of the wire between disks are desiredthe inflated length of the antenna can be many times that specifiedabove. Fine stranded wire may be employed for the antenna wire so thatit will not break or rupture after the antenna has been inflated andcollapsed several times. A sectional portion of the floating antennawith the casing inflated is illustrated in FIG. 5 and it should be notedthat the antenna wire 11 is adequately supported throughout its entirelength by the disks 7 thereby maintaining a fixed, constant physicalrelationship with respect to the casing 6 and with respect to thesurface of the fluid on which the antenna floats.

The overall length of the inflated antenna is predetermined by thefrequency band of the communication equipment with which it is employed.A cylindrical shape for the casing is preferred for the inflated antennasince the antenna wire is thereby positioned centrally therein and anyroll or turning of the floating antenna on the water on which it floatswill not alter the spacing of the wire from the water surface and aconstant antenna height is thereby maintained. The casing 6 protects theantenna wire from atmospheric variations and water spray while the disks7 position and support the Wire and minimize longitudinal twisting ofthe antenna.

When not in use or while being stored, the antenna is collapsed inlength. The compact size of the collapsed antenna facilitates its usewhere space is critical as for example, on lifeboats, rafts and aboardairplanes for transportation. The total number of disks may bepredetermined so as to result in a non-buoyant or sinkable antenna dueto the total weight of the disks as compared to the total antenna volumewhen the gas enclosed within the casing is released. This sinkablefeature is of prime importance under certain circumstances wheredetection is to be avoided, for instance, a floating antenna for asubmarine which suddenly submerges in order to avoid detection and cannot leave a buoy marking its prior location. It should be noted that thecasing 6 is free to flex since the space between the disks 7 is free ofany internal structure which would resist the outward or inward move;ment of the casing between the disks and so resist endwise collapse ofthe antenna.

It will be understood that various changes in the details, materials andarrangement of parts, which have been herein described and illustratedin order to explain the nature of this invention, may be made by thoseskilled in the art within the principle and scope of the invention asexpressed in the appended claims.

I claim:

1. A floating antenna for use with transmitting and receiving equipmentaboard a vessel to which the antenna may be connected, which comprises ahollow, closed, elongated, and lengthwise collapsible, watertight casingof electrically insulating material, a flexible metal antenna wireextending in a direction lengthwise of and within said casing, insulatedthereby from the exterior of the casing but having a circuit connectionon the exterior of one end wall of the casing, rigid spacer means whosedimension lengthwise of said casing is small as compared with thetransverse dimension of said casings, said spacer means disposed withinsaid casing at intervals along its length supporting said wire in spacedrelation to the peripheral wall of said casing when said casing isextended and each having a passage from face to face through which a gasmay pass, a towing connection to one end wall of said casing, theinterior of said casing between substantially all of said spacer meansbeing free of any structure which would prevent endwise collapse of saidcasing, and means adjacent and connected to the interior of the towedend of the casing for admitting thereto a gas under pressure and therebycausing extension of said casing to its full length from a collapsedcondition said full length being at least the product of the number ofspacer means and the transverse dimension of said casing.

2. The antenna according to claim 1, wherein each of said spacer meansis a member disposed tranversely across the interior of said casing,through which said antenna wire extends and having a passage open fromface to face for the passage of said gas.

3. The antenna according to claim 1, wherein said casing when extendedis cylindrical in shape, and each said wire supporting means is a diskof electrically insulating material through the interior face area ofwhich said antenna wire extends and having a passage from face to facethrough which said gas may pass in causing said extension of saidcasing.

4. The antenna according to claim 3, wherein said antenna wire isdisposed approximately centrally of the casing when said casing isextended.

5. The antenna according to claim 4, wherein said casing has anaccordian pleat construction and is formed of water impervious flexible,elastic sheet material enabling its collapse and extension endwise.

6. The antenna according to claim 5, wherein said gas admitting meansincludes a check valve in a conduit connected and opening into theinterior of said casing and a source of compressed gas connected to saidconduit for inflating endwise said casing.

7. The antenna according to claim 1, wherein said casing has anaccordian pleat construction enabling its collapse and extension endwiseand formed of water impervious, flexible sheet material.

8. The antenna according to claim 1, wherein said gas admitting meansincludes a check valve ina conduit connected to and opening into theinterior of one end wall of said casing.

'9. The antenna according to claim 8, and a source of compressed gasconnected to said conduit and through the valve to the interior of saidcasing.

10. The antenna according to claim 1, wherein said casing has itsperipheral wall formed of flexible, elastic sheet material.

11. The antenna according to claim 1, wherein said antenna wire isdisposed approximately centrally of the casing when the casing isextended whereby if the casing rolls about its longitudinal axis theheight of the antenna wire above the water in which the antenna may befloating remains fairly constant.

12. The antenna according to claim 1, wherein said towing connection isan insulated wire connected at its end, which is attached to one endwall of the casing, to said circuit connection of said antenna wire.

References Cited in the file of this patent UNITED STATES PATENTS1,116,835 Neumann Nov. 10, 1914 1,285,940 Chodakowski Nov. 26, 19181,557,049 Hammond Oct. 13, 1925 2,067,337 Polatzek Jan. 12, 19372,888,675 Pratt et a1 May 26, 1959 2,936,453 Coleman May 10, 1960

